Marianthi-Anna Kioumourtzoglou, ScD, a researcher at the Harvard School of Public Health in Boston, and colleagues collected data on 3,650 people listed in Danish National Registers who were diagnosed with ALS between 1982–2009. Their average age was 65. The researchers compared these patients with 365,000 healthy people. The researchers also identified 9,294 patients diagnosed with type 2 diabetes.

Fifty-five of the patients diagnosed with type 2 diabetes were later diagnosed with ALS, with an estimated odds ratio for ALS of 0.61 (95% confidence interval [CI], 0.46–0.80) for patients with diabetes. The average age of the diabetes-related diagnosis was 59.7 years. Older age at diagnosis for either disease was associated with lower risk for ALS, the researchers said. The odds ratio for first mention of diabetes was 1.66 (95% CI, 0.85–3.21) before age 40 years but 0.52 (95% CI, 0.39–0.70) for older ages.

"We found a protective association between type 2 diabetes and ALS," Kioumourtzoglou told HealthDay. "This is a very new finding."